dockerfile-parser-rs

The ultimate Rust library for parsing, modifying, and generating Dockerfiles.

Instructions

ADD
ARG
CMD
COPY
ENTRYPOINT
ENV
EXPOSE
FROM
LABEL
RUN
SHELL
STOPSIGNAL
USER
VOLUME
WORKDIR

Note: In addition to the official Dockerfile instructions, empty lines and comments are supported too.

Usage

Library

Run the following Cargo command in your project directory:

cargo add dockerfile-parser-rs

Example:

use std::path::PathBuf;

use dockerfile_parser_rs::Dockerfile;
use dockerfile_parser_rs::Instruction;
use dockerfile_parser_rs::ParseResult;

fn main() -> ParseResult<()> {
    let path = PathBuf::from("./Dockerfile");
    let mut dockerfile = Dockerfile::from(path.clone())?;

    dockerfile.instructions.push(Instruction::User {
        user: String::from("1001"),
        group: None,
    });

    dockerfile.dump(path)?;
    Ok(())
}

Binary

Run the following Cargo command in your project directory:

cargo install dockerfile-parser-rs

Example:

# prints the Dockerfile as JSON
dockerfile-parser-rs ./Dockerfile

Limitations

Instruction case sensitivity

The instructions are not case-sensitive. However, the library works only with uppercase instructions for simplicity and consistency. Using uppercase instructions is also a recommended convention in Dockerfile format documentation.

Instruction arguments ordering

Options for all instructions will be sorted in alphabetical order. This is done to ensure deterministic output when dumping a Dockerfile. The same applies to the ARG, ENV, and LABEL instructions when they have multiple key-value pairs defined on one line.

Here-documents (heredocs)

Here-documents allow redirection of subsequent Dockerfile lines to the input of RUN or COPY commands. If such a command contains a here-document, the Dockerfile considers the next lines until the line only containing a here-doc delimiter as part of the same command.

The here-documents syntax is only supported for the RUN instruction and only with the EOF delimiter. Make sure that here-documents are always terminated with an EOF character on a new line.

dockerfile-parser-rs 3.2.1